%A %T Investigation on Characteristics of Edible Oil Spectra with Terahertz Time-Domain Attenuated Total Reflection Spectroscopy %0 Journal Article %D 2018 %J SPECTROSCOPY AND SPECTRAL ANALYSIS %R 10.3964/j.issn.1000-0593(2018)07-2016-05 %P 2016-2020 %V 38 %N 07 %U {https://www.gpxygpfx.com/CN/abstract/article_9907.shtml} %8 2018-07-01 %X Edible oil is a significant source of human nutrition and energy, providing essential fatty acids for human body. Thus, the investigation on the optical properties of edible oils in THz region for component analysis and quality evaluation is considered to be of great importance. As a newly developed-technique, Terahertz time-domain attenuated total reflection spectroscopy can obtain the THz spectra through the interaction between sample and evanescent wave. Compared with Terahertz time-domain transmission or reflection spectroscopy, this technique can effectively avoid the influence of sample cell when measuring liquid samples such as edible oils, thus acquiring the optical parameters more accurately. The absorption spectra of soybean oil were measured via both Terahertz time-domain transmission spectroscopy and Terahertz time-domain attenuated total reflection spectroscopy. Compared with Terahertz time-domain transmission spectroscopy, the Terahertz time-domain attenuated total reflection spectroscopy showed greater advantages in acquiring the absorption coefficients and distribution of absorption peaks. Furthermore, the optical properties of soybean oil, walnut oil and grape seed oil were investigated by using Terahertz time-domain attenuated total reflection spectroscopy. In addition, the refractive index and absorption spectra of the three edible oils in the range from 1 to 1.8 THz were obtained. Using density functional theory, we also calculated the vibration and rotation modes of four kinds of principal components (hexadecanoic acid, octadecanoic acid, octadecenoic acid, and octadecadienoic acid) in THz region which were consistent well with the experimental results. In conclusion, the absorption peaks of edible oils in terahertz region are related to the components and contents of fatty acidsas well as result from their vibration and rotation modes. Moreover, this research may contribute to qualitative and quantitative components analysis as well as quality inspection of edible oils.